Question you would like to focus on (see "Macbeth Paper and Presentation" wiki page for ideas)
How was the theme, ambition, significant throughout the play?

Thesis (answer to the question)
Such powerful ambition may remove one’s ability to control greed, and emotion.

At least three major points that support your thesis
Macbeth's greed
King Duncan's death
Macbeth's death
At least one piece of textual evidence per major point